This invention relates to a hydrocarbon adsorbing or absorbing device that may be used in the induction system of a motor vehicle, and in particular, to a hydrocarbon adsorbing device having a configuration for providing an increased surface area of adsorbent material.
There continues to be a push to reduce emissions from internal combustion engines. One manner in which emissions are generated from an internal combustion engine is when the engine is shut off. Fuel which has been released from fuel injectors, but has not been consumed prior to engine shut down, may evaporate outwardly through the intake manifold, the intake air ducts and air filter to eventually escape into the atmosphere and contribute to air pollution.
In an effort to reduce these types of inadvertent evaporative emissions, many types of filters have been developed. Examples of filters for use in the intake system of a vehicle are found in U.S. Pat. No. 6,432,179 to Lobovsky et al. and U.S. Patent Application Publication No. U.S. 2002/0029693 to Sakakibara et al., both of which are incorporated herein by reference. The publication of Sakakibara et al. discloses several embodiments of hydrocarbon adsorbing devices having a case surrounding an inner cylinder portion. A hydrocarbon adsorbent material is provided in a chamber defined by the case and the inner cylinder portion. The inner cylinder portion has a central bore that extends through its length to permit induction air to pass therethrough, and also has windows that allow any hydrocarbons in the induction system to pass through a filter surrounding the inner cylinder portion to the hydrocarbon adsorbent material in the chamber to be adsorbed thereby.
The publication to Sakakibara et al. also discloses one embodiment, wherein the filter element is bent in a waveform in either the axial direction of the air intake passages or in a peripheral direction of the air intake passage. Sakakibara et al. indicates that providing the filter element in a waveform increases the surface area and efficiency of the adsorbent material. Although the waveform designs in the filter element disclosed by Sakakibara et al. increase the exposed surface area of the hydrocarbon adsorbent material in the chamber, it is an object of the present invention to provide a hydrocarbon adsorbing device with an even greater exposed surface area of hydrocarbon adsorbing material and having increased efficiency.